This invention relates in general to railcars and more particularly to an arrangement for enclosing the ends of hopper cars in order to reduce aerodynamic drag forces.
Railway hopper cars are widely used to carry a variety of bulk commodities. Open top hopper cars find their widest application in transporting coal, while various chemicals and petrochemicals are commonly transported in covered hopper cars.
Both open top and covered hopper cars have ends which are characterized by an open architectural style. The manner in which the cars are constructed results in an open region below each of the end slope sheets, and the open region is not covered or enclosed by the sides of the car. Frame members, ladders, brake equipment and the like are located at the ends of the hopper cars, but the ends are essentially open to air flow. It has been found that the open nature of the hopper car ends results in considerable aerodynamic drag which the locomotives must overcome and which therefore adds significantly to the fuel costs.
Because of the presence of the open ends of hopper cars, the effective inter-car gap is aerodynamically much greater than the actual distance between adjacent cars. For example, hopper cars that are 41 inches apart actually present a gap of approximately 90 inches between their end panels at the bottoms of the slope sheets. The open regions below the slope sheets together add approximately 49 inches to the effective inter-car gap. Consequently, the gap is large enough to enable large quantities of air to flow in behind one car and impinge upon the leading face of the next successive car. This creates a drag force which is multiplied by the number of hopper cars that are adjacent to each other in the consist. For a consist having a large number of hopper cars carrying coal or another cargo, the drag force that results from the open architectural style of the hopper cars can make a substantial contribution to the amount of fuel that is required to propel the consist.
The present invention has, as its principal goal, the reduction of the drag force that is encountered by railway hopper cars. In accordance with the invention, the hopper car ends are enclosed by aerodynamically efficient shrouds that decrease the effective inter-car gap and provide a configuration that is aerodynamically equivalent to a box car shape. Each shroud has a side plate which encloses the open side part of the hopper car and which also covers the adjacent vertical ribs on the side sheet of the car. An end plate of each shroud is applied to the end of the car and covers enough of the end to prevent significant air ingress. The shrouds are constructed of a lightweight material such as fiberglass, and their profile is specially shaped to achieve aerodynamic efficiency.